Previously I showed you how to set up SPF and DKIM on CentOS/RHEL mail server. Two common pieces of software that can do DKIM signing and verification on Linux are OpenDKIM and Amavis. In that tutorial I used Amavis, because at the time OpenDKIM isn’t included in any CentOS 8/RHEL 8 repository. As of now, OpenDKIM is included in the EPEL repository. Some folks prefer to use OpenDKIM so I will show you how in this tutorial.
What is DKIM?
DKIM (DomainKeys Identified Mail) is a type of TXT records in DNS that can help with preventing email spoofing and making legitimate emails delivered into the recipient’s inbox instead of spam folder. DKIM uses a private key to add a signature to emails sent from your domain. Receiving SMTP servers verify the signature by using the corresponding public key, which is published in your domain’s DNS records.
Read full tutorial here: https://www.linuxbabe.com/redhat/set-up-opendkim-centos-8-rhel-8
